Merge "Detaching HEAD when checking out the same commit."

1 files changed, 19 insertions, 1 deletions

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/RefUpdate.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/RefUpdate.java
index e6f8933389..24af944f2f 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/RefUpdate.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/RefUpdate.java
@@ -168,6 +168,17 @@ public abstract class RefUpdate {
 	private final Ref ref;
 
 	/**
+	 * Is this RefUpdate detaching a symbolic ref?
+	 *
+	 * We need this info since this.ref will normally be peeled of in case of
+	 * detaching a symbolic ref (HEAD for example).
+	 *
+	 * Without this flag we cannot decide whether the ref has to be updated or
+	 * not in case when it was a symbolic ref and the newValue == oldValue.
+	 */
+	private boolean detachingSymbolicRef;
+
+	/**
 	 * Construct a new update operation for the reference.
 	 * <p>
 	 * {@code ref.getObjectId()} will be used to seed {@link #getOldObjectId()},
@@ -254,6 +265,13 @@ public abstract class RefUpdate {
 	}
 
 	/**
+	 * Tells this RefUpdate that it is actually detaching a symbolic ref.
+	 */
+	public void setDetachingSymbolicRef() {
+		detachingSymbolicRef = true;
+	}
+
+	/**
 	 * Set the new value the ref will update to.
 	 *
 	 * @param id
@@ -596,7 +614,7 @@ public abstract class RefUpdate {
 
 			newObj = safeParse(walk, newValue);
 			oldObj = safeParse(walk, oldValue);
-			if (newObj == oldObj)
+			if (newObj == oldObj && !detachingSymbolicRef)
 				return store.execute(Result.NO_CHANGE);
 
 			if (newObj instanceof RevCommit && oldObj instanceof RevCommit) {